Approximately 15 percent of patients recover from hepatitis C virus (HCV) infection, while 85 percent become persistently infected with various degrees of associated chronic liver disease. In this study, comparisons will be made among patients who recover rapidly, those who have delayed recovery, those with persistent infection and stable chronic disease, and those with rapidly progressive, fatal infections. The parameters measured will be viral burden (initially and over time), HCV genotype, the number of viral quasi-species (extent of viral heterogeneity) at the time of infection and subsequently, neutralizing antibody responses, and, if appropriate technology is available, cytotoxic T cell responses. The goal is to determine if any of these parameters can predict outcome and hence serve as adjuncts to therapeutic decisions, particularly decisions regarding early intervention.